Classical philosophy and Darwinian biology are far more compatible than is usually assumed. In fact, looking at either from the standpoint of the other can enrich and deepen our appreciation of both. From a Darwinian point of view, the theories of Plato and Aristotle deserve to be taken very seriously. From the classical point of view, Darwinian biology is much less reductionist than its enemies suppose.

Friday, March 22, 2013

Physical Reductionism, Greedy & Generous

I return here to the
topic of a previous post: two distinct types of reductionism.Critics of evolutionary ethics frequently
argue that the latter involves both types of reductionism without often
distinguishing them.Here
is Andrew Ferguson arguing in defense of Thomas Nagel’s book (see previous
posts on this book), in the Weekly
Standard:

Naturalism is also called “materialism,” the view that only
matter exists; or “reductionism,” the view that all life, from tables to
daydreams, is ultimately reducible to pure physics; or “determinism,” the view
that every phenomenon, including our own actions, is determined by a
preexisting cause, which was itself determined by another cause, and so on back
to the Big Bang. The naturalistic project has been greatly aided by
neo-Darwinism, the application of Darwin’s theory of natural selection to human
behavior, including areas of life once assumed to be nonmaterial: emotions and
thoughts and habits and perceptions.

Ferguson squeezes a lot of “isms”
very tightly together when in fact they need to be moved apart.I don’t doubt his view that many modern
Darwinists fancy themselves to be materialists and determinists.However, while they may all or mostly be the
latter, very few are really the former.A
genuine materialist would have to believe that life is dependent upon soul
particles and heat upon particles of phlogiston.Does anyone believe that anymore?Today “materialism” generally means only that
one does not believe in substance dualism.

I would argue at any rate that
physical reductionism is tenable in modern science or indeed any science in one
sense but not in another.Consider this
analogy: when you are watching a DVD, what are you seeing?It looks as though you are watching and
listening to human beings interacting with one another.In fact, you are watching an image produced
by pixels on a screen.They human beings
you seem to be watching are not really there.The motives and emotions they seem to present are fictions.Even the actors themselves may be dead and
gone.Only the pixels are real.

Greedy reductionism would
attempt to reduce all phenomena to the motion of molecules in the radical sense
that only the particles are real; the larger realm of human beings and human
action would not really exist anymore than the faces on TV.This kind of reductionism is held by some
theorists, as in the theory of eliminative materialism.According to the latter, mental states are
fictions just as phlogiston was a fiction; only physical brain states are
real.This view is radical and has not
seemed plausible to very many philosophers or scientists.

A second kind of reductionism (let
us call it generous reductionism) argues only that all phenomena including
human beings and their minds, subsist in matter and can, for some purposes of
analysis, be reduced to the level of molecules.To see what this means, let us take the example of a baseball moving
through the air from the pitcher’s mound toward home plate.I think that even the most romantic baseball
fan (I am such a fan) will concede that the ball consists entirely of
molecules.There is no immaterial spirit,
malevolent or otherwise, in the ball (however much a superstitious batter might
think otherwise).Reducing the ball to
the molecular level for analysis may tell us something interesting about the
object: why it weighs what it does and how it interacts with the flow of
air.Such reduction, however, tells us
very little about the physics of the pitch.The ball would behave very differently if the very same constituents
were arranged in the form of a cube and rolled rather than pitched.I could hit that.

To understand the pitch, one has
to ignore the molecular level and consider the ball as a much larger whole,
thrown by a human arm, moving through the air.Anyone trying to analyze the ball as a cloud of molecules would have to
come around to viewing that cloud in the same way that a fan views it and his
molecular-eye view would be mere baggage.

If the flight of a lively ball is
irreducible to the molecular level, so much more is the action of lively human
beings.The ball as an intact physical
object, the pitcher and the batter and the fans, are all entirely real and are
irreducible to their molecular components.So also with evolutionary theory.While genes may be no more than complex molecules, their phenotypical vehicles
are robustly real and the subsistence of the former over long periods of time
cannot be explained by chemical analysis.To understand why I share genes with a very wide range of organisms, I
must consider the sturm und drang of fully expressed organisms competing and
proliferating on land, sea, and air.Biology is legitimately subject to generous reductionism, but not to
greedy reductionism.

I suppose, then that modern
materialism, naturalism, and reductionism pose no threat to the common sense
understanding of human beings and their actions.Our brains, like our bodies, are made up of
organs; the organs of cells; the cells of complex molecules and those in turn
of simpler molecules and atoms.I hold,
with Aristotle, that all form is the form of something and that moving down the
chain of suborganization leads to material constituents.Likewise, Aristotle and I suppose that form
is irreducible to material and must be understood in all its robust
complexity.

2 comments:

"the flight of a lively ball is irreducible to the molecular level": this is far (by any standard) conensual in the fields of physics. It is actually a very debated topic tightly connected to the concept of "Quantum coherence" and "Wave Function Collapse" (see wikipedia). Some interpretations of quantum physics, indeed would argue that macroscopic phenomena (the flight of a ball) may indeed not be *in practice* reducible to quantum operations (e.g., because of the limited computational tools at our disposal) but they still *ARE* in essence a quantum phenomenon.

K: I remain very dubious about the reduction of the ball to quantum phenomena. It seems to me unlikely the quantum state(s) of any particle can be responsible for the shape of the ball. The shape of the ball is a property of a very large collection of quantum operations. It might be possible to include those operations in a description of the ball though, as we agree, there are practical limitations. It just seems to me that a complete description has to include features that belong to the whole rather than the parts.